Bathroom Extractor Fan Starting - Digital Shower

[mache]

Hi All,

Would appreciate your thoughts on how I might initate a bathroom extractor fan starting. No pull cord starters wanted by the way.

Extractor unit itself is mounted in loft out of bathroom. Shower unit is a wireless controlled digital shower valve pumped.
What I would like to do is have the extractor run for the duration of the shower operating and then turn off after shower unit stops (built in overrun timer on fan unit.)

Clearly I can't use a normal extractor fan starter that might typically run from a shower isolator switch, as the digital control unit will be permantley live waiting for its start function from the wireless control unit. So therefore I am thinking if there is a commercially available device that could sense the running load on the shower supply circuit which could trigger the extractor fan start. The digital shower unit is a pump mixer unit and has a max declared load of 200W when running.

Any advise greatly received as I could only find traditional shower installations mentioned when trying to find possible previous threads.

Shower valve supplied from 6 amp RCBO, valve location is outside of bathroom area as is the extractor fan itself.
Regards
Martin.

 

[internet]

Hi, Excuse me butting in as I'm not an electrician but would a relay powered from that pump work for this situation?

 

[mache]

Hi, Excuse me butting in as I'm not an electrician but would a relay powered from that pump work for this situation?

I had wondered about that but would involve hacking into the digital mixer unit to pick up a feed from the pump drive motor. clearly I don't want to modify that unit if possible due to manufacturers warrenty etc. Unless I can find a load sensing relay to put in supply line to only come on when pump unit is in demand rather than in standby mode and then drop out when the load drops. I might try a quick google see what comes up

 

[internet]

I had wondered about that but would involve hacking into the digital mixer unit to pick up a feed from the pump drive motor. clearly I don't want to modify that unit if possible due to manufacturers warrenty etc. Unless I can find a load sensing relay to put in supply line to only come on when pump unit is in demand rather than in standby mode and then drop out when the load drops. I might try a quick google see what comes up

What is the make and model?

 

[mache]

Mira Platinum Dual Valve Pumped 1.1796.006

 

[internet]

Mira Platinum Dual Valve Pumped 1.1796.006

I did a few searches for some sort of fan controller but nothing is really coming up. Wondering if nothing like it exists as most situations the fan comes on with lights. I did find out the operating frequency is 433.05 MHz to 434.79 . It may be possible to construct an arduino based device with something like NRF905 and relay, that reads the on/offf signal from the controller that switches the extractor.

 

[mache]

I did a few searches for some sort of fan controller but nothing is really coming up. Wondering if nothing like it exists as most situations the fan comes on with lights. I did find out the operating frequency is 433.05 MHz to 434.79 . It may be possible to construct an arduino based device with something like NRF905 and relay, that reads the on/offf signal from the controller that switches the extractor.

Thanks Internet, I think your right nothing currently exists for this sort of direct use. I think your NRF905 is a bit beyond my current skill set. I will contact Mira technical I think and ask if they can advise a suitable connection to could use to hook onto a relay and see what they say. Thanks for your input.

 

[Wiresandthings]

Not 100% sure about the shower in question, you could however use a suitably rated flow switch fitted to the output pipe connected to the fan, this would act as a light switch and you would still benefit from a timer over run facility, I've never done this but see no reason why it wouldn't work

 

[Richard Burns]

If you do not want to make any changes to the existing setup then you would need a current sensing clamp with a relay output that would operate a contactor to run the fan.
This would be somewhat expensive.
It would also not necessarily provide fan overrun to clear the room after use.
Another alternative would be to use an occupancy sensor to operate the fan.
Or a simple plate switch outside the room, or even a retractive switch.